Category: hardware
Hits: 7013

My current job is to build and setup SMS gateway at low cost. It is a part of my project in the office to have a UPS monitoring and alert notification system. The main objective is to beat the supplier that came out with expensive GSM box (Motorola). It was cost about RM3000.00.

My GSM Box is China made, built with Siemens TC35 circuitry, serial connection to PC and cost about RM700.00

The main problem to use Megatec Netagent SMS server software with Siemens TC35 is the software is hard to detect the GSM box. By default, the GSM box setting is like below,

  1. Baud = 9600
  2. Parity = None
  3. Data bits = 8
  4. Stop bit = 1
  5. Flow control = None


But when I got this GSM box, it connected to PC at 115200kb/s baud rate whenever I tested it with hyperterminal. But, Megatec SMS server won’t connect using this baud rate setting.

What I have to do is to set the baud rate to auto. So that the SMS server software can detect it automatically whatever rate it wants to use. To do so, I follow below steps.

  1. Connect the GSM box with hyperterminal using current baud rate and setting.
  2. Type AT and Enter, it will reply OK. That’s mean the connection is ok.
  3. To change baud rate, type, AT+IPR=0 and Enter.
  4. Restart the equipment.
  5. Test the connection with the new baud rate setting.
  6. Type AT and Enter, it will reply OK. That’s mean the connection is ok.


After that, you can test the connection with Megatec SMS server software.

Additional: How can I know what is the current baud rate if it is now default setting? You need to try one by one all baud rate setting and leave other settings like above until you find the good connection using hyperterminal . Maybe it takes a lot of time. The good connection it whenever you type, the hyperterminal will display a keystroke and can respond to any simple AT commands. To check all settings in GSM box, you can type AT&V and Enter.

This is a GSM Box Siemens TC35.

 

Zip slot for SIM card. To take the slot out, use pen to push the yellow notch beside the slot.